The former Pennsylvania senator took first place in Colorado, Minnesota and Missouri.

But as NPR Senior Washington Editor Ron Elving points out in a column that will be on It's All Politics later, Tuesday's caucuses and "beauty contest" (in Missouri) basically drew relatively tiny turnouts largely composed of conservatives who are very committed to Santorum and were willing to gather even if no delegates were at stake — not a cross-section of Republicans.

That's why, as Ron notes, some news outlets are using the world "meaningless" to describe Tuesday's outcomes.

Still, many of the morning-after analyses are looking at Santorum's wins as at least dealing a blow to front-runner Mitt Romney and potentially something more:

-- Santorum "has dramatically resuscitated a campaign that was bordering on irrelevant," according to Politico.

-- The former senator's victories are "a major boon to his previously floundering presidential campaign," says The Hill.